module: support main w/o extension, pjson cache

This adds support for ensuring that the top-level main into Node is
supported loading when it has no extension for backwards-compat with
NodeJS bin workflows.

In addition package.json caching is implemented in the module lookup
process.

PR-URL: https://github.com/nodejs/node/pull/18728
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

1 files changed, 8 insertions, 21 deletions

diff --git a/lib/module.js b/lib/module.js
index 5ee537f1572..c3250608ebe 100644
--- a/lib/module.js
+++ b/lib/module.js
@@ -24,7 +24,6 @@
 const NativeModule = require('native_module');
 const util = require('util');
 const { decorateErrorStack } = require('internal/util');
-const internalModule = require('internal/module');
 const { getURLFromFilePath } = require('internal/url');
 const vm = require('vm');
 const assert = require('assert').ok;
@@ -35,6 +34,7 @@ const {
   internalModuleReadJSON,
   internalModuleStat
 } = process.binding('fs');
+const internalModule = require('internal/module');
 const preserveSymlinks = !!process.binding('config').preserveSymlinks;
 const experimentalModules = !!process.binding('config').experimentalModules;
 
@@ -43,10 +43,9 @@ const errors = require('internal/errors');
 module.exports = Module;
 
 // these are below module.exports for the circular reference
-const Loader = require('internal/loader/Loader');
+const internalESModule = require('internal/process/modules');
 const ModuleJob = require('internal/loader/ModuleJob');
 const createDynamicModule = require('internal/loader/CreateDynamicModule');
-let ESMLoader;
 
 function stat(filename) {
   filename = path.toNamespacedPath(filename);
@@ -447,7 +446,6 @@ Module._resolveLookupPaths = function(request, parent, newReturn) {
   return (newReturn ? parentDir : [id, parentDir]);
 };
 
-
 // Check the cache for the requested file.
 // 1. If a module already exists in the cache: return its exports object.
 // 2. If the module is native: call `NativeModule.require()` with the
@@ -460,22 +458,10 @@ Module._load = function(request, parent, isMain) {
     debug('Module._load REQUEST %s parent: %s', request, parent.id);
   }
 
-  if (isMain && experimentalModules) {
-    (async () => {
-      // loader setup
-      if (!ESMLoader) {
-        ESMLoader = new Loader();
-        const userLoader = process.binding('config').userLoader;
-        if (userLoader) {
-          ESMLoader.isMain = false;
-          const hooks = await ESMLoader.import(userLoader);
-          ESMLoader = new Loader();
-          ESMLoader.hook(hooks);
-        }
-      }
-      Loader.registerImportDynamicallyCallback(ESMLoader);
-      await ESMLoader.import(getURLFromFilePath(request).pathname);
-    })()
+  if (experimentalModules && isMain) {
+    internalESModule.loaderPromise.then((loader) => {
+      return loader.import(getURLFromFilePath(request).pathname);
+    })
     .catch((e) => {
       decorateErrorStack(e);
       console.error(e);
@@ -578,7 +564,8 @@ Module.prototype.load = function(filename) {
   Module._extensions[extension](this, filename);
   this.loaded = true;
 
-  if (ESMLoader) {
+  if (experimentalModules) {
+    const ESMLoader = internalESModule.ESMLoader;
     const url = getURLFromFilePath(filename);
     const urlString = `${url}`;
     const exports = this.exports;